Steve from YouTube page Steve’s Retro Gaming has come across an old Commodore Business Machines service manual for the C64, Amiga and Commodore PC’s series computers. This is an awesome find and shows a wealth of information on Commodore parts and prices from 1993.
In addition if you’re interested in Commodore 64 related copy protection Steve has an website that’s an excellent resource called 64copyprotection.com that’s worth a look.